Halo ejection in distant radio galaxies: jet feedback in massive galaxy formation
We present results from a Keck optical and near IR spectroscopic study of the giant emission line halos of the z > 3 High Redshift Radio Galaxies (HiZRGs) 4C 41.17, 4C 60.07 and B2 0902+34. The outer regions of these halos show quiet kinematics with typical velocity dispersions of a few hundred km s^(−1) and velocity shears consistent with rotation. The inner regions contain shocked, clumpy cocoons of gas closely associated with the radio lobes with disturbed kinematics and expansion velocities and/or velocity dispersions > 1000 km s^(−1). We also find evidence for the ejection of chemically enriched material in 4C 41.17 up to a distance of ~60 kpc along the radio-axis. We infer that these HiZRGs are undergoing a final jet-induced phase of star formation with the ejection of most of their interstellar medium before evolving to become "red and dead" Elliptical galaxies.